US9520437B2 - Flexible APS X-ray imager with MOTFT pixel readout and a pin diode sensing element - Google Patents
Flexible APS X-ray imager with MOTFT pixel readout and a pin diode sensing element Download PDFInfo
- Publication number
- US9520437B2 US9520437B2 US14/460,054 US201414460054A US9520437B2 US 9520437 B2 US9520437 B2 US 9520437B2 US 201414460054 A US201414460054 A US 201414460054A US 9520437 B2 US9520437 B2 US 9520437B2
- Authority
- US
- United States
- Prior art keywords
- layer
- array
- forming
- depositing
- etch stop
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active, expires
Links
- 239000011521 glass Substances 0.000 claims abstract description 26
- 239000000758 substrate Substances 0.000 claims abstract description 24
- 238000000151 deposition Methods 0.000 claims abstract description 18
- 239000004065 semiconductor Substances 0.000 claims abstract description 15
- 239000011810 insulating material Substances 0.000 claims abstract description 14
- 238000004519 manufacturing process Methods 0.000 claims abstract description 13
- 229910052751 metal Inorganic materials 0.000 claims abstract description 10
- 239000002184 metal Substances 0.000 claims abstract description 10
- 238000004891 communication Methods 0.000 claims abstract description 9
- 238000000034 method Methods 0.000 claims description 55
- 230000008569 process Effects 0.000 claims description 34
- 229910021417 amorphous silicon Inorganic materials 0.000 claims description 29
- 239000000463 material Substances 0.000 claims description 18
- 229910052760 oxygen Inorganic materials 0.000 claims description 11
- 229910052717 sulfur Inorganic materials 0.000 claims description 11
- 238000005530 etching Methods 0.000 claims description 9
- 229910021420 polycrystalline silicon Inorganic materials 0.000 claims description 9
- 229910052711 selenium Inorganic materials 0.000 claims description 9
- 239000012212 insulator Substances 0.000 claims description 7
- 229910000510 noble metal Inorganic materials 0.000 claims description 6
- 239000000203 mixture Substances 0.000 claims description 5
- 229910007541 Zn O Inorganic materials 0.000 claims description 4
- 230000003321 amplification Effects 0.000 claims description 4
- 150000001875 compounds Chemical class 0.000 claims description 4
- 238000003199 nucleic acid amplification method Methods 0.000 claims description 4
- 238000000059 patterning Methods 0.000 claims description 3
- 229910052814 silicon oxide Inorganic materials 0.000 claims description 3
- 229910002480 Cu-O Inorganic materials 0.000 claims description 2
- 229910015675 MoO3−x Inorganic materials 0.000 claims description 2
- 229910017299 Mo—O Inorganic materials 0.000 claims description 2
- 239000004642 Polyimide Substances 0.000 claims description 2
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 claims description 2
- 229910003077 Ti−O Inorganic materials 0.000 claims description 2
- 229910008936 W—O Inorganic materials 0.000 claims description 2
- 229910007746 Zr—O Inorganic materials 0.000 claims description 2
- KPUWHANPEXNPJT-UHFFFAOYSA-N disiloxane Chemical class [SiH3]O[SiH3] KPUWHANPEXNPJT-UHFFFAOYSA-N 0.000 claims description 2
- 229910052732 germanium Inorganic materials 0.000 claims description 2
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 claims description 2
- 229920001721 polyimide Polymers 0.000 claims description 2
- 229920000642 polymer Polymers 0.000 claims description 2
- 229910000077 silane Inorganic materials 0.000 claims description 2
- 239000011669 selenium Substances 0.000 claims 5
- 238000010030 laminating Methods 0.000 claims 2
- BUGBHKTXTAQXES-UHFFFAOYSA-N Selenium Chemical compound [Se] BUGBHKTXTAQXES-UHFFFAOYSA-N 0.000 claims 1
- 229910004541 SiN Inorganic materials 0.000 claims 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims 1
- 239000010410 layer Substances 0.000 description 87
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 9
- 229920002457 flexible plastic Polymers 0.000 description 8
- 238000003491 array Methods 0.000 description 7
- 230000035945 sensitivity Effects 0.000 description 7
- QPJSUIGXIBEQAC-UHFFFAOYSA-N n-(2,4-dichloro-5-propan-2-yloxyphenyl)acetamide Chemical compound CC(C)OC1=CC(NC(C)=O)=C(Cl)C=C1Cl QPJSUIGXIBEQAC-UHFFFAOYSA-N 0.000 description 5
- 239000003990 capacitor Substances 0.000 description 4
- 238000000576 coating method Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 238000007689 inspection Methods 0.000 description 4
- 229910044991 metal oxide Inorganic materials 0.000 description 4
- 150000004706 metal oxides Chemical class 0.000 description 4
- 238000004806 packaging method and process Methods 0.000 description 4
- 239000011248 coating agent Substances 0.000 description 3
- 239000010408 film Substances 0.000 description 3
- 239000011159 matrix material Substances 0.000 description 3
- 239000010409 thin film Substances 0.000 description 3
- 230000004888 barrier function Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 229910052804 chromium Inorganic materials 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000001312 dry etching Methods 0.000 description 2
- 239000003292 glue Substances 0.000 description 2
- 238000005286 illumination Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000000623 plasma-assisted chemical vapour deposition Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 239000004593 Epoxy Substances 0.000 description 1
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 229910017817 a-Ge Inorganic materials 0.000 description 1
- -1 acryl Chemical group 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 238000000231 atomic layer deposition Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000002591 computed tomography Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 229910021419 crystalline silicon Inorganic materials 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 239000005357 flat glass Substances 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 238000003702 image correction Methods 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 239000011147 inorganic material Substances 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 238000003475 lamination Methods 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 229910021421 monocrystalline silicon Inorganic materials 0.000 description 1
- 230000008450 motivation Effects 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 239000012044 organic layer Substances 0.000 description 1
- 239000011368 organic material Substances 0.000 description 1
- 229920000620 organic polymer Polymers 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 229920005596 polymer binder Polymers 0.000 description 1
- 239000002491 polymer binding agent Substances 0.000 description 1
- 229920005591 polysilicon Polymers 0.000 description 1
- 239000002243 precursor Substances 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 229910052715 tantalum Inorganic materials 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 150000003624 transition metals Chemical class 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- 238000001039 wet etching Methods 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
- H01L27/14643—Photodiode arrays; MOS imagers
- H01L27/14658—X-ray, gamma-ray or corpuscular radiation imagers
- H01L27/14663—Indirect radiation imagers, e.g. using luminescent members
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
- H01L27/14601—Structural or functional details thereof
- H01L27/14609—Pixel-elements with integrated switching, control, storage or amplification elements
- H01L27/14612—Pixel-elements with integrated switching, control, storage or amplification elements involving a transistor
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
- H01L27/14683—Processes or apparatus peculiar to the manufacture or treatment of these devices or parts thereof
- H01L27/14692—Thin film technologies, e.g. amorphous, poly, micro- or nanocrystalline silicon
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
- H01L27/14643—Photodiode arrays; MOS imagers
- H01L27/14658—X-ray, gamma-ray or corpuscular radiation imagers
-
- H01L27/308—
-
- H01L51/4293—
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K30/00—Organic devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation
- H10K30/40—Organic devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation comprising a p-i-n structure, e.g. having a perovskite absorber between p-type and n-type charge transport layers
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K39/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic radiation-sensitive element covered by group H10K30/00
- H10K39/30—Devices controlled by radiation
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K39/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic radiation-sensitive element covered by group H10K30/00
- H10K39/30—Devices controlled by radiation
- H10K39/36—Devices specially adapted for detecting X-ray radiation
Definitions
- This invention generally relates to active matrix pixel sensor X-ray imagers using a MOTFT backplane and a PIN diode sensor array.
- MOTFT Metal Oxide Thin Film Transistors
- APS active pixel sensor
- a-Si amorphous silicon
- X-ray scintillator/a-Si TFT/a-Si PIN photodiode combination One of the most popular X-ray image detectors is the X-ray scintillator/a-Si TFT/a-Si PIN photodiode combination.
- the X-ray scintillator converts the X-rays into visible light which is then detected by the a-Si PIN photodiode in an image sensing pixel of a two dimensional visible imager.
- Each sensing pixel comprises a switch transistor made of an a-Si TFT, a storage capacitor and a sensing element made of an a-Si PIN photodiode.
- Such pixel circuit is often called a passive pixel sensing (PPS) circuit. This combination is preferred because of its simple and inexpensive construction.
- the PIN photodiode plane on top of the TFT backplane it is preferred to have the PIN photodiode plane on top of the TFT backplane so that the metal lines and transistors in the backplane will not block visible light coming from the X-ray scintillator.
- the fabrication of the a-Si PIN photodiode plane on top of (i.e. subsequent to) a MOTFT backplane can be an issue.
- the MOTFT backplane will have a difficult time surviving the high temperature and the ambience of a-Si fabrication.
- the fabrication process is constrained to form the a-Si PIN photodiode plane first and then form the MOTFT backplane on top of the a-Si photodiode plane.
- the key problem in this orientation is that the metal lines and transistors in the MOTFT backplane will block a significant portion of the incident light from the top mounted scintillator.
- the fill factor (the ratio of sensing area to the total pitch area) for MOTFT backplanes is very poor. Also, the fill factor issue gets worse for high resolution imager arrays because of the smaller pixel size (i.e. higher pixels density).
- MOTFT backplanes for digital X-ray imagers
- APS active pixel sensor
- PPS passive pixel sensor
- the fill factor is even worse for APS than for PPS.
- circuit compensation techniques are used to compensate for stability and uniformity, more transistors and control lines are needed, which makes the fill factor problem even worse.
- APS active pixel sensor
- the desired objects of the instant invention are achieved in accordance with an embodiment of a method of fabricating an X-ray imager including the steps of providing a rigid support member with a surface, forming an etch stop layer on the surface of the rigid support member, and depositing sensing element blanket layers on the etch stop layer.
- the sensing element blanket layers are separated into an array of sensing elements.
- a layer of insulating material is deposited on the array of sensing elements to form a planarized surface and contacts are formed on the planarized surface in communication with individual sensing elements in the array through the layer of insulating material.
- a MOTFT backplane is positioned on the planarized surface and in electrical communication with the contacts to provide a sensor plane/MOTFT backplane interconnected combination.
- a support carrier is attached to the MOTFT backplane and the rigid support member is removed.
- a scintillator is laminated on the array of sensing elements.
- an X-ray imager includes a stack of blanket layers of a-Si or compound semiconductor material including a first p or n doped layer, an intrinsic layer, and a second n or p doped layer, separated into an array of PIN photodiodes by isolation patterning on the top doped layer.
- a layer of insulating material is positioned on the array of PIN photodiodes forming a planarized surface that includes contacts on the planarized surface in electrical communication with individual photodiodes in the array through the layer of insulating material.
- An array of MOTFTs in a passive pixel sensor or an active pixel sensor configuration backplane is positioned on the planarized surface and in electrical communication with the contacts, to provide a sensor plane/MOTFT backplane interconnected combination.
- a flexible support carrier is positioned on the MOTFT backplane and a scintillator is laminated on the array of PIN photodiodes.
- FIG. 1 is a simplified layer diagram illustrating a first intermediate structure in a process for fabricating X-ray imagers in accordance with the present invention
- FIG. 2 is a simplified layer diagram illustrating a second intermediate structure in a process for fabricating X-ray imagers in accordance with the present invention
- FIG. 3 is a simplified layer diagram illustrating a third intermediate structure in a process for fabricating X-ray imagers in accordance with the present invention.
- FIG. 4 is a simplified layer diagram illustrating a final embodiment for a flexible improved X-ray image detector incorporating an X-ray scintillator/a-Si photo diode combination with a MOTFT backplane in accordance with the present invention.
- a rigid support member (hereinafter glass substrate 12 ) includes a flat glass panel, which is a preferred support member and will be used as an example herein although other materials may be used in specific applications. It should also be understood that the thickness of glass substrate 12 is not critical except that it must be thick enough to prevent any bending during the fabrication process and will generally be as thin as practical to reduce the ultimate etching time. Also, glass substrate 12 (i.e. the rigid support member) should be easy to remove once the fabrication process has been completed.
- etch stop layer 14 is deposited on glass substrate 12 and includes any material that will stop the etching process once glass substrate 12 has been removed.
- etching of glass substrate 12 is best performed by hydrofluoric acid (HF) and the best etch stop material is a thin layer of noble metal, such as Au, Pt, Pd, or a thin layer of transition metal in 5B and 6B columns of the periodic table, such as V, Nb, Ta, Cr, Mo, and W, and mixtures or multilayer stacks thereof.
- HF hydrofluoric acid
- the best etch stop material is a thin layer of noble metal, such as Au, Pt, Pd, or a thin layer of transition metal in 5B and 6B columns of the periodic table, such as V, Nb, Ta, Cr, Mo, and W, and mixtures or multilayer stacks thereof.
- Such enhancement can be provided by optional thin glue layers (not visible within layer 14 ) such as Cr, Ti, Ni, or mixtures thereof applied to the top and/or bottom of layer 14 . It should be specifically noted that once glass substrate 12 is removed any noble metal (e.g. Au used in etch stop layer 14 ) can be recycled or reclaimed to reduce the cost.
- any noble metal e.g. Au used in etch stop layer 14
- etch stop layer 14 is a thin layer of amorphous silicon (a-Si) deposited on glass substrate 12 by PECVD.
- a-Si amorphous silicon
- PECVD PECVD
- a-Si amorphous silicon
- the resulting poly-Si can survive the HF etch process. Since the crystallization step is carried out before any additional layer deposition and TFT processing, the high temperature step does not cause any problem.
- borosilicate type of glasses used in the flat panel industry can stand for temperature cycles to approximately 600° C. Such glass can withstand the polycrystalline process and has been used in the low temperature polysilicon (TPS) display industry.
- Etch stop layer 14 should be as thin as possible to reduce the time required for application and removal if required or preferred. It has been found that a thickness of less than 200 nm provides sufficient protection and, preferably, etch stop layer 14 is 100 nm or thinner.
- a thickness of less than 200 nm provides sufficient protection and, preferably, etch stop layer 14 is 100 nm or thinner.
- the insulating protection layer would have to be much thicker than 200 nm to withstand the etching removal of the glass substrate.
- a first semiconductor layer 16 is deposited on etch stop layer 14 and may be either n or p type conductivity.
- a layer 18 of intrinsic semiconductor material is deposited on layer 16 and a layer 20 of opposite conductivity material (i.e. p or n) is deposited on layer 18 .
- the three layers form a sensing element plane or in this case a PIN diode detector (photodiode) plane, generally designated 22 , which is a preferred embodiment for its efficiency.
- PIN diode detector photodiode
- layers 16 , 18 , and 20 are p-i-n photodiode blanket layers, or sensing element blanket layers, deposited over etch stop layer 14 and no masks are required.
- all three layers 16 , 18 , and 20 are formed with one semiconductor material, such as amorphous silicon, a-Si, (as shown marked in FIG. 1 ) or amorphous germanium, a-Ge, (not shown) or their alloy, for the simplicity of formation and the sensitivity to visible light.
- the doped and intrinsic semiconductor layers 16 , 18 , and 20 are formed with different compound semiconductor films such that a heterojunction photodiode is formed.
- Such arrangement can be used to reduce the dark current and optimize photodetectivity.
- heterojunction type of PIN diodes include oxygen deficient Zn—O, In—Zn—O, Ti—O, Ta—O, W—O, or Zr—O film for the n-layer, Cd—S, Cd—O, Cu—O, Cu—S, Cu—In—O, Cu—In—Se, Cu—In—S, Cu—Cd—O, Cu—Cd—Se, Cu—Cd—S, Cu—Ga—O, Cu—Ga—Se, Cu—In—Ga—Se, or Cu—In—Ga—S, for the i-layer, Mo—O, Ag x MoO 3-x , and/or AgAlO 3 for the p-layer.
- the i-layer can also be made in multiple sub-layers for special needs or to optimize hole and electron extractions at the corresponding contact electrodes.
- Doped layers 16 and 20 when provided with a wider semiconductor energy gap, can reduce the dark current under reverse bias and thus reduce the sensor noise and increase the detectivity of the sensor array. Doped layers 16 and 20 are especially useful in APS circuits when used for a pixel readout circuit and, when the system noise is improved, to level the imaging sensitivity, which is limited by a noise PIN sensing element in each pixel.
- the carrier densities in the p or n doped layers are typically larger than 10 17 cm ⁇ 3 , and, preferably, larger than 10 18 cm ⁇ 3 .
- the carrier density in the intrinsic or i-layer is typically smaller than 10 16 cm ⁇ 3 , and, preferably, smaller than 10 15 cm ⁇ 3 .
- the PIN structure is patterned into individual pixels by etching upper layer 20 as illustrated in FIG. 1 .
- lateral charge dispersion needs to be further controlled, both layer 20 and part or all of layer 18 are etched within each image pixel (not shown in FIG. 1 ).
- layer 16 is denoted as an n-type a-Si layer and layer 20 is denoted as a p-type a-Si layer.
- layer 16 is denoted as an n-type a-Si layer and layer 20 is denoted as a p-type a-Si layer.
- the order can be reversed. Selection is often made to match the convenience and the simplification of the readout circuits in each pixel and in peripheral areas of the image array.
- a-Si is illustrated in FIG. 1 as the PIN sensor element, part or all of the layers 16 , 18 and 20 can also be in nano-crystalline or micro-crystalline forms.
- an insulating planarization layer 24 is deposited over patterned layer 20 by any convenient process and using any suitable insulating material. It could be made with organic material, inorganic material, or combinations thereof in blend form or in stack with multiple sublayers.
- organic insulator material for layer 24 include photo-patternable organic polymers, such as epoxy based SU-8 by MicroChem, polyimide (such as Toray 4100 series or 1600 series, JNC PIF-series), positive acryl resin such as JSR PC548, AZ SOG series, silane or siloxane based photo patternable polymers (such as Fuji FF series and JNC silamax series).
- Inorganic insulator materials for layer 24 include SiN, SiON, and SiO.
- layer 24 is formed in an inorganic/organic bilayer, with 50 nm-500 nm thick for the inorganic insulator layer and 100 nm-200 nm thick for the organic insulator layer.
- Vias 26 are formed through insulating planarization layer 24 and electrically conductive contacts are formed through vias 26 into electrical contact with the upper surface of individual photodiodes through insulating planarization layer 24 .
- the via-hole pattern in layer 24 can be achieved by a standard photo-exposure process when the organic insulator is directly photo-patternable.
- Via-holes 26 are formed in the organic layer after developing. These holes are used as a built-in mask and the inorganic insulator layer in the via-hole area can be removed with a dry-etching process.
- a MOTFT backplane 30 is fabricated directly or otherwise positioned on insulating planarization layer 24 and in electrical contact with PIN diodes in plane 22 through vias 26 .
- the via 26 process can be combined with one of the metal layer processes in MOTFT 30 . The process is thus further simplified.
- MOTFT backplane 30 is an active pixel sensor which, because light enters the structure through the bottom, will not hinder or otherwise reduce the sensitivity.
- a typical APS pixel readout comprises three TFTs, one storage capacitor and several control/power lines.
- Such APS pixel readout has been used in silicon-wafer based CMOS imagers (Z. Huang and T. Ando, “A novel amplified image sensor with a-Si:H photoconductor and MOS transistor”, IEEE Trans. Electron Devices , Vol. 37, p. 1432 (1990)).
- CMOS imagers Z. Huang and T. Ando, “A novel amplified image sensor with a-Si:H photoconductor and MOS transistor”, IEEE Trans. Electron Devices , Vol. 37, p. 1432 (1990)
- a wafer based pixel readout is too expensive to use.
- a TFT based back-panel becomes the only viable solution.
- Amorphous silicon TFTs have been used for PPS readouts for X-ray imagers (Larry E, Antonuk et al., “Large-Area Flat-Panel Amorphous Silicon Imager” , Proc. SPIE. , V. 2432, p. 216 (1995)).
- PPS readout becomes challenging to be used when pixel pitch and sensor pad dimension is reduced to levels below 100 mm ⁇ 100 um, at which the photo-response under X-ray illumination is reduced to levels comparable to various noises existing in the sensor system.
- an APS pixel readout becomes a promising approach.
- High pixel density APS pixel readout with thin-film-transistors can be arranged in stack relationship over the sensing element 22 .
- An amorphous silicon TFT is limited for such application due to its low mobility (and thus limited space for pixel readout) and operation stability.
- LTPS-TFT is difficult to use for its high fixed pattern noise due to performance inhomogeneity.
- the MOTFT has mobility and operation stability as good as the LTPS-TFT (over 80 cm 2 /Vsec and over 100 coulomb electrons passing the TFT without performance change), but with Vth and ON current uniformity as good as amorphous silicon TFTs.
- AMOLED Active matrix organic light emitting displays
- the MOTFT In addition to the high mobility and operation stability, the MOTFT possesses superb low “OFF” current under reverse Vgs bias, often reaching the limit of testing equipment.
- the corresponding quantum noise is thus smaller than 50 electrons.
- Such high switch ratio TFT has not been seen in the thin film transistor field, which enables an image array with a video rate, with 2D array comprising more than 1000 ⁇ 1000 pixels (i.e., >105 gate lines), with large dynamic range and with noise level only achieved with single crystalline silicon CMOS arrays.
- the APS pixel readout circuit bares similar performance requirement as the 2T1C AMOLED pixel driver.
- the TFT operating under analog model in both cases requires high uniformity and stability on operation current and threshold voltages.
- the uniformity performance demonstrated in AMOLED thus validates the MOTFT described above for APS image arrays.
- Such a MOTFT backplane can be fabricated over the PIN photodiode array 22 of FIG. 2 at a temperature and an environment compatible to the underlying sensor array: i.e., without damage to the sensor array.
- the APS readout is stacked behind the PIN sensor array and light illumination from X-ray scintillator from the bottom (see FIG. 4 )
- the entire pixel pitch area can be used for APS pixel readout circuits.
- Typical APS readout in three transistor and one capacitor form can be laid out within a 20 ⁇ m ⁇ 20 ⁇ m area, which corresponds to a pixel density of 1250 pixels per square inch.
- additional packaging structure is formed on the upper surface thereof as illustrated in FIG. 3 .
- the additional packaging structure can be either flexible or ridged, in this specific example the additional packaging structure is a flexible plastic carrier 32 .
- Flexible plastic carrier 32 is thick enough to act as the mechanical support for the X-ray sensor device after glass substrate 12 is removed. Also, the top side of the X-ray sensor device is protected by flexible plastic carrier 32 .
- a coating 34 of adhesive material e.g. glue or the like
- a barrier coating at the interface between carrier 32 and coating 34 or at both surfaces of carrier 32 can be added.
- etch stop layer 14 can be removed by a different etching process if required. For example, when Au or other metal is used as etch stop layer 14 it blocks light from PIN diode plane 22 and, in addition, will save money by removing and reusing the material.
- etch stop layer 14 is a thin poly-silicon film it is generally transparent to light emission and may simply be left in place. However, since some light may be blocked it is or may be preferable to remove the poly-silicon layer. When removing is desirable, the poly-silicon can be removed by fluorine based dry etching. Since packaging and glass substrate removal are carried out at low temperatures ( ⁇ 100 degrees Celsius), the present novel process allows more options in material selection for flexible plastic carrier 32 .
- Scintillator layer 40 can include any of the well-known materials that convert X-rays to visible light.
- Layer 40 can be made into either flexible or predefined, non-flat conformable forms (examples include structured crystalline scintillator such as CsI:Tl, or scintillator particles in a polymer binder, such as Gd 2 O 2 S:Tb). Methods have been known to experts in the field.
- the resulting structure is a flexible or conformable X-ray image detector in which the higher mobility and stability of the MOTFTs and greater resolution through smaller pixels is or can be realized.
- the use of an active pixel sensor configuration greatly improves sensitivity, readout frame time, dynamic range and control of the X-ray image detector.
- some amplification of the sensed signals can be incorporated into the APS configuration to a level above the noise of the readout data line.
- the stacking configuration and the high I on /I off ratio in a MOTFT with dimensions reaching design rules enables the APS pixel readout with signal amplifier with desired magnification factors: thus, APS with variable gains is realized.
- Another example is incorporating a reset or a compensating circuit in the pixel readout to further improve the operation stability or responding speed and minimizing signal processing time by software in a computer system. High image quality, large dynamic range, video rate, X-ray imager can be achieved with such an image array.
- the flexible/conformable image array disclosed in this invention enables many applications never achieved before.
- the APS pixel readout improves the X-ray detection sensitivity to levels only previously achieved with single crystal silicon wafer based CMOS imagers.
- the sensor structure shown in FIG. 4 enables large area sensor arrays to be made into, for example, cylindrical form and fits the need for tomo-synthesis and cone beam X-ray CT. Such a cylindrical array possesses uniform pixel/angle ratio and eliminates complicated image reconstruction calculations by software after a CT scan.
- the high mobility MOTFT and fast frame time X-ray sensing enables real time diagnostic or monitoring/inspection during surgeon operations.
- the applications can go beyond the medical field and into industrial X-ray inspection. Examples include defect inspection in oil pipes and frame structure inspection of airplane or sailing boats.
- the present invention provides new and improved processes for fabricating a flexible/comformable X-ray image detector incorporating the X-ray scintillator/PIN photo diode combination with a MOTFT backplane.
- the new and improved processes for fabricating an X-ray imager use a fewer number of process steps which are simple to perform.
- the new and improved processes for fabricating an X-ray imager are specifically designed to make the fabrication of the PIN photo diode plane compatible with the fabrication of the MOTFT backplane and the lamination of the scintillator thereon. Further, the processes result in the formation of a flexible/conformable X-ray image detector that can more easily fit with the contours of the object being X-rayed.
- the process allows the combination of the MOTFT backplane and the PIN diode plane, the higher mobility and stability of the MOTFTs and greater resolution through smaller pixels and the use of an active pixel sensor configuration with amplification if desired greatly improves the sensitivity, dynamic range, frame time and control of the X-ray image detector.
- a flat metal sheet (such as aluminum, copper, stainless steel) can be used. Such metal supporting sheet can be removed by wet etching.
- the imager structure and the corresponding process flow disclosed in this invention can be extended beyond X-ray or radiation image arrays.
- a curved image array with a large field of view and with uniform pixel/view angle ratio can be achieved.
- the high mobility, high current switch ratio MOTFT enables high pixel density, high pixel count image array with high sensitivity and fast image readout with high frame rate.
- the constant pixel/view angle ratio enables uniform image readout over large view angles without image distortion. It also eliminates tedious image correction post image collection with software with wafer-based flat camera or a set of flat cameras.
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- General Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- Electromagnetism (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Health & Medical Sciences (AREA)
- Toxicology (AREA)
- Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Nanotechnology (AREA)
- Solid State Image Pick-Up Elements (AREA)
- Measurement Of Radiation (AREA)
Abstract
Description
Claims (20)
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US14/460,054 US9520437B2 (en) | 2014-08-14 | 2014-08-14 | Flexible APS X-ray imager with MOTFT pixel readout and a pin diode sensing element |
PCT/US2015/045083 WO2016025731A1 (en) | 2014-08-14 | 2015-08-13 | Flexible aps x-ray imager with motft pixel readout and a pin diode sensing element |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US14/460,054 US9520437B2 (en) | 2014-08-14 | 2014-08-14 | Flexible APS X-ray imager with MOTFT pixel readout and a pin diode sensing element |
Publications (2)
Publication Number | Publication Date |
---|---|
US20160049441A1 US20160049441A1 (en) | 2016-02-18 |
US9520437B2 true US9520437B2 (en) | 2016-12-13 |
Family
ID=55302738
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US14/460,054 Active 2035-07-10 US9520437B2 (en) | 2014-08-14 | 2014-08-14 | Flexible APS X-ray imager with MOTFT pixel readout and a pin diode sensing element |
Country Status (2)
Country | Link |
---|---|
US (1) | US9520437B2 (en) |
WO (1) | WO2016025731A1 (en) |
Families Citing this family (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
IL246003B (en) * | 2016-06-02 | 2019-03-31 | W P Energy Ltd | Multiband energy harvesting |
CN108447941B (en) * | 2017-02-16 | 2019-10-18 | 群创光电股份有限公司 | The pixel circuit and X-ray detector of X-ray detector |
US10856413B2 (en) * | 2017-04-07 | 2020-12-01 | University Of Central Florida Research Foundation, Inc. | Segmented stretchable/conformable electronic and optoelectronic circuit on stretchable backplane |
KR102466811B1 (en) * | 2017-12-12 | 2022-11-11 | 엘지디스플레이 주식회사 | Flexible digital x-ray detector panel and the manufacturing method thereof |
US10608041B2 (en) * | 2018-04-12 | 2020-03-31 | Palo Alto Research Center Incorporated | Bendable x-ray detector with TFT backplane in the neutral plane |
CN109216391B (en) | 2018-09-11 | 2021-02-19 | 京东方科技集团股份有限公司 | Detection panel, manufacturing method thereof and detection device |
US10825855B2 (en) | 2018-12-13 | 2020-11-03 | Palo Alto Research Center Incorporated | Flexible x-ray sensor with integrated strain sensor |
KR102609302B1 (en) * | 2019-08-14 | 2023-12-01 | 삼성전자주식회사 | Method for fabricating semiconductor package |
CN110838467A (en) * | 2019-10-18 | 2020-02-25 | 武汉华星光电技术有限公司 | Manufacturing method of low-temperature polycrystalline silicon substrate and low-temperature polycrystalline silicon substrate |
CN111134705B (en) * | 2020-01-21 | 2023-10-13 | 上海奕瑞光电子科技股份有限公司 | Radiation image detector and manufacturing method thereof |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20120211063A1 (en) * | 2009-03-17 | 2012-08-23 | Jong-Jan Lee | Back Contact Solar Cell with Organic Semiconductor Heterojunctions |
US20140167046A1 (en) * | 2012-12-13 | 2014-06-19 | Chan- Long Shieh | Pixelated imager with motfet and process |
US20150263078A1 (en) * | 2014-03-17 | 2015-09-17 | Chan-Long Shieh | Flexible tft backpanel by glass substrate removal |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5376561A (en) * | 1990-12-31 | 1994-12-27 | Kopin Corporation | High density electronic circuit modules |
GB2462591B (en) * | 2008-08-05 | 2013-04-03 | Cambridge Display Tech Ltd | Organic thin film transistors and methods of making the same |
KR101819757B1 (en) * | 2009-06-17 | 2018-01-17 | 더 리젠츠 오브 더 유니버시티 오브 미시간 | Photodiode and other sensor structures in flat-panel x-ray imagers and method for improving topological uniformity of the photodiode and other sensor structures in flat-panel x-ray imagers based on thin-film electronics |
JP5728250B2 (en) * | 2011-03-01 | 2015-06-03 | キヤノン株式会社 | Radiation detection apparatus, scintillator panel, manufacturing method thereof, and radiation detection system |
-
2014
- 2014-08-14 US US14/460,054 patent/US9520437B2/en active Active
-
2015
- 2015-08-13 WO PCT/US2015/045083 patent/WO2016025731A1/en active Application Filing
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20120211063A1 (en) * | 2009-03-17 | 2012-08-23 | Jong-Jan Lee | Back Contact Solar Cell with Organic Semiconductor Heterojunctions |
US20140167046A1 (en) * | 2012-12-13 | 2014-06-19 | Chan- Long Shieh | Pixelated imager with motfet and process |
US8962377B2 (en) * | 2012-12-13 | 2015-02-24 | Cbrite Inc. | Pixelated imager with motfet and process |
US20150263078A1 (en) * | 2014-03-17 | 2015-09-17 | Chan-Long Shieh | Flexible tft backpanel by glass substrate removal |
US9240437B2 (en) * | 2014-03-17 | 2016-01-19 | Cbrite Inc. | Flexible TFT backpanel by glass substrate removal |
Also Published As
Publication number | Publication date |
---|---|
US20160049441A1 (en) | 2016-02-18 |
WO2016025731A1 (en) | 2016-02-18 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US9520437B2 (en) | Flexible APS X-ray imager with MOTFT pixel readout and a pin diode sensing element | |
US7902512B1 (en) | Coplanar high fill factor pixel architecture | |
US9985061B2 (en) | Light detection device with integrated photodiode and thin film transistor | |
US20100054418A1 (en) | X-ray detecting element | |
US10852447B2 (en) | Panel for flexible digital x-ray detector and method for manufacturing the same | |
WO2017028477A1 (en) | Ray detector | |
WO2016195000A1 (en) | Photosensor substrate | |
WO2016163347A1 (en) | Photosensor substrate | |
US10386503B2 (en) | Array substrate for digital X-ray detector, digital X-ray detector including the same, and method for manufacturing the same | |
WO2016002610A1 (en) | Imaging panel and x-ray imaging system provided with said imaging panel | |
US20190058001A1 (en) | X ray flat panel detector and fabrication method thereof | |
WO2016195001A1 (en) | Active matrix substrate | |
GB2570401A (en) | X-Ray detector | |
US11209557B2 (en) | Array substrate for digital X-ray detector, digital X-ray detector including the same, and method for manufacturing the same | |
US7968358B2 (en) | Digital radiographic flat-panel imaging array with dual height semiconductor and method of making same | |
KR102670831B1 (en) | Digital x-ray detector having light shielding layer and method of fabricating thereof | |
CN108550601A (en) | The radiographic array preparation of metal oxide thin-film transistor for the mask count with reduction | |
WO2016195005A1 (en) | Active matrix substrate | |
US11515354B2 (en) | Thin film transistor array substrate for digital X-ray detector device and digital X-ray detector device including the same | |
WO2015163288A1 (en) | Light detection device | |
US20210313399A1 (en) | Imaging device | |
US11335706B2 (en) | Thin film transistor array substrate for high-resolution digital X-ray detector and high-resolution digital X-ray detector including the same | |
US10992884B2 (en) | Imaging panel and method for producing same | |
US9947704B1 (en) | Method of recovery of MOTFT backplane after a-Si photodiode fabrication | |
JP2007093257A (en) | Radiation detector |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: CBRITE INC., CALIFORNIA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:SHIEH, CHAN-LONG;YU, GANG;SIGNING DATES FROM 20140903 TO 20140905;REEL/FRAME:040008/0308 |
|
STCF | Information on status: patent grant |
Free format text: PATENTED CASE |
|
AS | Assignment |
Owner name: FULL STRENGTH GROUP LIMITED, HONG KONG Free format text: SECURITY INTEREST;ASSIGNOR:CBRITE INC.;REEL/FRAME:045653/0983 Effective date: 20170825 Owner name: FULL STRENGTH GROUP LIMITED, HONG KONG Free format text: SECURITY INTEREST;ASSIGNOR:CBRITE INC.;REEL/FRAME:045653/0823 Effective date: 20170519 |
|
AS | Assignment |
Owner name: ABC SERVICES GROUP, INC., SOLELY IN ITS CAPACITY AS ASSIGNEE FOR THE BENEFIT OF CREDITORS OF CBRITE INC., CALIFORNIA Free format text: RELEASE BY SECURED PARTY;ASSIGNOR:FULL STRENGTH GROUP LIMITED;REEL/FRAME:048069/0427 Effective date: 20180727 Owner name: ABC SERVICES GROUP, INC., SOLELY IN ITS CAPACITY A Free format text: RELEASE BY SECURED PARTY;ASSIGNOR:FULL STRENGTH GROUP LIMITED;REEL/FRAME:048069/0427 Effective date: 20180727 Owner name: CBRITE INC., CALIFORNIA Free format text: RELEASE BY SECURED PARTY;ASSIGNOR:FULL STRENGTH GROUP LIMITED;REEL/FRAME:048069/0427 Effective date: 20180727 |
|
AS | Assignment |
Owner name: FANTASY SHINE LIMITED, HONG KONG Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:ABC SERVICES GROUP, INC.;REEL/FRAME:049879/0645 Effective date: 20181024 |
|
AS | Assignment |
Owner name: FULL STRENGTH GROUP LIMITED, HONG KONG Free format text: CORRECTIVE ASSIGNMENT TO CORRECT THE LIST OF PROPERTIES SO THAT IT DOES NOT INCLUDE US PATENT NO. 8233212 PREVIOUSLY RECORDED AT REEL: 004653 FRAME: 0983. ASSIGNOR(S) HEREBY CONFIRMS THE ASSIGNMENT;ASSIGNOR:CBRITE INC.;REEL/FRAME:052377/0913 Effective date: 20170825 Owner name: FULL STRENGTH GROUP LIMITED, HONG KONG Free format text: CORRECTIVE ASSIGNMENT TO CORRECT THE LIST OF PROPERTIES SO THAT IT DOES NOT INCLUDE US PATENT NO. 8233212 PREVIOUSLY RECORDED AT REEL: 045653 FRAME: 0823. ASSIGNOR(S) HEREBY CONFIRMS THE ASSIGNMENT;ASSIGNOR:CBRITE INC.;REEL/FRAME:052377/0853 Effective date: 20170519 Owner name: FANTASY SHINE LIMITED, HONG KONG Free format text: CORRECTIVE ASSIGNMENT TO CORRECT THE LIST OF PROPERTIES SO THAT IT DOES NOT INCLUDE US PATENT NO. 8233212 PREVIOUSLY RECORDED ON REEL 049879 FRAME 0645. ASSIGNOR(S) HEREBY CONFIRMS THE ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:ABC SERVICES GROUP, INC.;REEL/FRAME:052384/0761 Effective date: 20181024 Owner name: ABC SERVICES GROUP, INC., SOLELY IN ITS CAPACITY AS ASSIGNEE FOR THE BENEFIT OF CREDITORS OF CBRITE INC., CALIFORNIA Free format text: CORRECTIVE ASSIGNMENT TO CORRECT THE LIST OF PROPERTIES SO THAT IT DOES NOT INCLUDE US PATENT NO. 8233212 PREVIOUSLY RECORDED ON REEL 048069 FRAME 0427. ASSIGNOR(S) HEREBY CONFIRMS THE RELEASE BY SECURED PARTY;ASSIGNOR:FULL STRENGTH GROUP LIMITED;REEL/FRAME:052384/0832 Effective date: 20180727 Owner name: CBRITE INC., CALIFORNIA Free format text: CORRECTIVE ASSIGNMENT TO CORRECT THE LIST OF PROPERTIES SO THAT IT DOES NOT INCLUDE US PATENT NO. 8233212 PREVIOUSLY RECORDED ON REEL 048069 FRAME 0427. ASSIGNOR(S) HEREBY CONFIRMS THE RELEASE BY SECURED PARTY;ASSIGNOR:FULL STRENGTH GROUP LIMITED;REEL/FRAME:052384/0832 Effective date: 20180727 Owner name: FULL STRENGTH GROUP LIMITED, HONG KONG Free format text: CORRECTIVE ASSIGNMENT TO CORRECT THE LIST OF PROPERTIES SO THAT IT DOES NOT INCLUDE US PATENT NO. 8233212 PREVIOUSLY RECORDED AT REEL: 045653 FRAME: 0983. ASSIGNOR(S) HEREBY CONFIRMS THE ASSIGNMENT;ASSIGNOR:CBRITE INC.;REEL/FRAME:052377/0913 Effective date: 20170825 |
|
FEPP | Fee payment procedure |
Free format text: MAINTENANCE FEE REMINDER MAILED (ORIGINAL EVENT CODE: REM.); ENTITY STATUS OF PATENT OWNER: SMALL ENTITY |
|
FEPP | Fee payment procedure |
Free format text: SURCHARGE FOR LATE PAYMENT, SMALL ENTITY (ORIGINAL EVENT CODE: M2554); ENTITY STATUS OF PATENT OWNER: SMALL ENTITY |
|
MAFP | Maintenance fee payment |
Free format text: PAYMENT OF MAINTENANCE FEE, 4TH YR, SMALL ENTITY (ORIGINAL EVENT CODE: M2551); ENTITY STATUS OF PATENT OWNER: SMALL ENTITY Year of fee payment: 4 |